Mercurial > dovecot > core-2.2
annotate src/lib-index/mail-hash.c @ 29:e9375147c0cb HEAD
Added write_full() which is a simple wrapper around write() meant for
writing into files.
When there's too much deleted data in index files, they're now compressed
when the index is being opened.
| author | Timo Sirainen <tss@iki.fi> |
|---|---|
| date | Mon, 26 Aug 2002 02:46:59 +0300 |
| parents | 1b34ec11fff8 |
| children | 1ab58549429d |
| rev | line source |
|---|---|
| 0 | 1 /* Copyright (C) 2002 Timo Sirainen */ |
| 2 | |
| 3 #include "lib.h" | |
| 4 #include "primes.h" | |
| 5 #include "mmap-util.h" | |
|
29
e9375147c0cb
Added write_full() which is a simple wrapper around write() meant for
Timo Sirainen <tss@iki.fi>
parents:
5
diff
changeset
|
6 #include "write-full.h" |
| 0 | 7 #include "mail-index.h" |
| 8 #include "mail-index-util.h" | |
| 9 #include "mail-hash.h" | |
| 10 | |
| 11 #include <stdio.h> | |
| 12 #include <fcntl.h> | |
| 13 | |
| 14 /* Minimum record count for a hash file. By default, the hash file size is | |
| 15 the number of messages * 3, and it's rebuilt after the file is 3/4 full. | |
| 16 Use only primes as hash file sizes. */ | |
| 17 #define MIN_HASH_SIZE 109 | |
| 18 | |
| 19 /* When rebuilding hash, make it 30% full */ | |
| 20 #define MIN_PERCENTAGE 30 | |
| 21 | |
| 22 /* Try rebuilding hash sometimes soon after it's 60% full */ | |
| 23 #define REBUILD_PERCENTAGE 60 | |
| 24 | |
| 25 /* Force a rebuild when hash is 80% full */ | |
| 26 #define FORCED_REBUILD_PERCENTAGE 80 | |
| 27 | |
| 28 #define HASH_FUNC(uid) (uid * 2) | |
| 29 | |
| 30 struct _MailHash { | |
| 31 MailIndex *index; | |
| 32 | |
| 33 unsigned int size; | |
| 34 | |
| 35 int fd; | |
| 36 char *filepath; | |
| 37 | |
| 38 void *mmap_base; | |
| 39 size_t mmap_length; | |
| 40 | |
| 41 MailHashHeader *header; | |
| 42 unsigned int dirty_mmap:1; | |
| 43 unsigned int modified:1; | |
| 44 }; | |
| 45 | |
| 46 static int mmap_update(MailHash *hash) | |
| 47 { | |
| 48 if (!hash->dirty_mmap) | |
| 49 return TRUE; | |
| 50 | |
| 51 if (hash->mmap_base != NULL) | |
| 52 (void)munmap(hash->mmap_base, hash->mmap_length); | |
| 53 | |
| 54 hash->mmap_base = mmap_rw_file(hash->fd, &hash->mmap_length); | |
| 55 if (hash->mmap_base == MAP_FAILED) { | |
| 56 hash->mmap_base = NULL; | |
| 57 hash->header = NULL; | |
| 58 index_set_error(hash->index, | |
| 59 "hash: mmap() failed with file %s: %m", | |
| 60 hash->filepath); | |
| 61 return FALSE; | |
| 62 } | |
| 63 | |
| 64 if (hash->mmap_length <= sizeof(MailHashHeader) || | |
| 65 (hash->mmap_length - sizeof(MailHashHeader)) % | |
| 66 sizeof(MailHashRecord) != 0) { | |
| 67 /* hash must be corrupted, rebuilding should have noticed | |
| 68 if it was only partially written. */ | |
| 69 hash->header = NULL; | |
| 70 index_set_error(hash->index, "Corrupted hash file %s: %m", | |
| 71 hash->filepath); | |
| 72 return FALSE; | |
| 73 } | |
| 74 | |
| 75 hash->dirty_mmap = FALSE; | |
| 76 hash->header = hash->mmap_base; | |
| 77 return TRUE; | |
| 78 } | |
| 79 | |
| 80 static MailHash *mail_hash_new(MailIndex *index) | |
| 81 { | |
| 82 MailHash *hash; | |
| 83 | |
| 84 hash = i_new(MailHash, 1); | |
| 85 hash->fd = -1; | |
| 86 hash->index = index; | |
| 87 hash->filepath = i_strconcat(index->filepath, ".hash", NULL); | |
| 88 hash->dirty_mmap = TRUE; | |
| 89 | |
| 90 index->hash = hash; | |
| 91 return hash; | |
| 92 } | |
| 93 | |
| 94 int mail_hash_create(MailIndex *index) | |
| 95 { | |
| 96 i_assert(index->lock_type == MAIL_LOCK_EXCLUSIVE); | |
| 97 | |
| 98 return mail_hash_rebuild(mail_hash_new(index)); | |
| 99 } | |
| 100 | |
| 101 static int mail_hash_lock_and_rebuild(MailHash *hash) | |
| 102 { | |
| 103 if (!hash->index->set_lock(hash->index, MAIL_LOCK_EXCLUSIVE)) | |
| 104 return FALSE; | |
| 105 return mail_hash_rebuild(hash); | |
| 106 } | |
| 107 | |
| 108 int mail_hash_open_or_create(MailIndex *index) | |
| 109 { | |
| 110 MailHash *hash; | |
| 111 | |
| 112 hash = mail_hash_new(index); | |
| 113 | |
| 114 hash->fd = open(hash->filepath, O_RDWR); | |
| 115 if (hash->fd == -1) | |
| 116 return mail_hash_lock_and_rebuild(hash); | |
| 117 | |
| 118 if (!mmap_update(hash)) { | |
| 119 /* mmap() failure is fatal */ | |
| 120 mail_hash_free(hash); | |
| 121 return FALSE; | |
| 122 } | |
| 123 | |
| 124 /* verify that this really is the hash file for wanted index */ | |
| 125 if (hash->header->indexid != index->indexid) { | |
| 126 /* mismatch - just recreate it */ | |
| 127 (void)munmap(hash->mmap_base, hash->mmap_length); | |
| 128 hash->mmap_base = NULL; | |
| 129 hash->dirty_mmap = TRUE; | |
| 130 | |
| 131 return mail_hash_lock_and_rebuild(hash); | |
| 132 } | |
| 133 | |
| 134 hash->size = (hash->mmap_length - sizeof(MailHashHeader)) / | |
| 135 sizeof(MailHashRecord); | |
| 136 return TRUE; | |
| 137 } | |
| 138 | |
| 139 void mail_hash_free(MailHash *hash) | |
| 140 { | |
| 141 hash->index->hash = NULL; | |
| 142 | |
| 143 if (hash->mmap_base != NULL) { | |
| 144 (void)munmap(hash->mmap_base, hash->mmap_length); | |
| 145 hash->mmap_base = NULL; | |
| 146 } | |
| 147 | |
| 148 (void)close(hash->fd); | |
| 149 i_free(hash->filepath); | |
| 150 i_free(hash); | |
| 151 } | |
| 152 | |
| 153 static int file_set_size(int fd, off_t size) | |
| 154 { | |
| 155 char block[1024]; | |
| 156 unsigned int i, full_blocks; | |
| 157 off_t pos; | |
| 158 | |
| 159 /* try truncating it to the size we want. if this succeeds, the written | |
| 160 area is full of zeros - exactly what we want. however, this may not | |
| 161 work at all, in which case we fallback to write()ing the zeros. */ | |
| 162 if (ftruncate(fd, size) != -1 && lseek(fd, 0, SEEK_END) == size) | |
| 163 return lseek(fd, 0, SEEK_SET) == 0; | |
| 164 | |
| 165 /* skip the existing data in file */ | |
| 166 pos = lseek(fd, 0, SEEK_END); | |
|
5
1b34ec11fff8
Message data is parsed in blocks (no longer entirely mmap()ed). Several
Timo Sirainen <tss@iki.fi>
parents:
0
diff
changeset
|
167 if (pos == -1) |
| 0 | 168 return FALSE; |
| 169 size -= pos; | |
| 170 | |
| 171 memset(block, 0, sizeof(block)); | |
| 172 | |
| 173 /* write in 1kb blocks */ | |
| 174 full_blocks = size / sizeof(block); | |
| 175 for (i = 0; i < full_blocks; i++) { | |
|
29
e9375147c0cb
Added write_full() which is a simple wrapper around write() meant for
Timo Sirainen <tss@iki.fi>
parents:
5
diff
changeset
|
176 if (write_full(fd, block, sizeof(block)) < 0) |
| 0 | 177 return FALSE; |
| 178 } | |
| 179 | |
| 180 /* write the remainder */ | |
| 181 i = size % sizeof(block); | |
|
29
e9375147c0cb
Added write_full() which is a simple wrapper around write() meant for
Timo Sirainen <tss@iki.fi>
parents:
5
diff
changeset
|
182 return i == 0 ? TRUE : write_full(fd, block, i) == 0; |
| 0 | 183 } |
| 184 | |
| 185 static int hash_rebuild_to_file(MailIndex *index, int fd, | |
| 186 unsigned int hash_size, | |
| 187 unsigned int messages_count) | |
| 188 { | |
| 189 MailHashHeader *hdr; | |
| 190 MailHashRecord *rec; | |
| 191 MailIndexRecord *idx_rec; | |
| 192 void *mmap_base; | |
| 193 unsigned int i, count; | |
| 194 size_t mmap_length; | |
| 195 size_t new_size; | |
| 196 | |
| 197 /* fill the file with zeros */ | |
| 198 new_size = sizeof(MailHashHeader) + hash_size * sizeof(MailHashRecord); | |
| 199 if (!file_set_size(fd, (off_t) new_size)) { | |
| 200 index_set_error(index, | |
| 201 "Failed to fill temp hash to size %lu: %m", | |
| 202 (unsigned long) new_size); | |
| 203 return FALSE; | |
| 204 } | |
| 205 | |
| 206 /* now, mmap() it */ | |
| 207 mmap_base = mmap_rw_file(fd, &mmap_length); | |
| 208 if (mmap_base == MAP_FAILED) { | |
| 209 index_set_error(index, "mmap()ing temp hash failed: %m"); | |
| 210 return FALSE; | |
| 211 } | |
| 212 | |
| 213 i_assert(mmap_length == new_size); | |
| 214 | |
| 215 /* we have empty hash file mmap()ed now. fill it by reading the | |
| 216 messages from index. */ | |
| 217 rec = (MailHashRecord *) ((char *) mmap_base + sizeof(MailHashHeader)); | |
| 218 idx_rec = index->lookup(index, 1); | |
| 219 for (count = 0; idx_rec != NULL; count++) { | |
| 220 i = HASH_FUNC(idx_rec->uid) % hash_size; | |
| 221 rec[i].uid = idx_rec->uid; | |
| 222 rec[i].position = INDEX_FILE_POSITION(index, idx_rec); | |
| 223 idx_rec = index->next(index, idx_rec); | |
| 224 } | |
| 225 | |
| 226 if (count != messages_count) { | |
| 227 /* mark this as an error but don't fail because of it. */ | |
| 228 INDEX_MARK_CORRUPTED(index); | |
| 229 index_set_error(index, "Missing messages while rebuilding " | |
| 230 "hash file %s - %u found, header says %u", | |
| 231 index->filepath, count, messages_count); | |
| 232 } | |
| 233 | |
| 234 /* setup header */ | |
| 235 hdr = mmap_base; | |
| 236 hdr->indexid = index->indexid; | |
| 237 hdr->used_records = count; | |
| 238 | |
| 239 return munmap(mmap_base, mmap_length) == 0; | |
| 240 } | |
| 241 | |
| 242 int mail_hash_sync_file(MailHash *hash) | |
| 243 { | |
| 244 if (!hash->modified) | |
| 245 return TRUE; | |
| 246 hash->modified = FALSE; | |
| 247 | |
| 248 if (msync(hash->mmap_base, hash->mmap_length, MS_SYNC) == 0) | |
| 249 return TRUE; | |
| 250 else { | |
| 251 index_set_error(hash->index, "msync() failed for %s: %m", | |
| 252 hash->filepath); | |
| 253 return FALSE; | |
| 254 } | |
| 255 } | |
| 256 | |
| 257 int mail_hash_rebuild(MailHash *hash) | |
| 258 { | |
| 259 MailIndexHeader *index_header; | |
| 260 const char *path; | |
| 261 unsigned int hash_size; | |
| 262 int fd; | |
| 263 | |
| 264 i_assert(hash->index->lock_type == MAIL_LOCK_EXCLUSIVE); | |
| 265 | |
| 266 /* first get the number of messages in index */ | |
| 267 index_header = hash->index->get_header(hash->index); | |
| 268 | |
| 269 /* then figure out size for our hash */ | |
| 270 hash_size = primes_closest(index_header->messages_count * 100 / MIN_PERCENTAGE); | |
| 271 if (hash_size < MIN_HASH_SIZE) | |
| 272 hash_size = MIN_HASH_SIZE; | |
| 273 | |
| 274 /* create the hash in a new temp file */ | |
| 275 fd = mail_index_create_temp_file(hash->index, &path); | |
| 276 if (fd == -1) | |
| 277 return FALSE; | |
| 278 | |
| 279 if (!hash_rebuild_to_file(hash->index, fd, hash_size, | |
| 280 index_header->messages_count)) { | |
| 281 (void)close(fd); | |
| 282 (void)unlink(path); | |
| 283 return FALSE; | |
| 284 } | |
| 285 | |
| 286 if (fsync(fd) == -1) { | |
| 287 index_set_error(hash->index, | |
| 288 "fsync() failed with temp hash %s: %m", path); | |
| 289 (void)close(fd); | |
| 290 (void)unlink(path); | |
| 291 return FALSE; | |
| 292 } | |
| 293 | |
| 294 /* replace old hash file with this new one */ | |
| 295 if (rename(path, hash->filepath) == -1) { | |
| 296 index_set_error(hash->index, "rename(%s, %s) failed: %m", | |
| 297 path, hash->filepath); | |
| 298 | |
| 299 (void)close(fd); | |
| 300 (void)unlink(path); | |
| 301 return FALSE; | |
| 302 } | |
| 303 | |
| 304 /* switch fds */ | |
| 305 if (hash->fd != -1) | |
| 306 (void)close(hash->fd); | |
| 307 hash->size = hash_size; | |
| 308 hash->fd = fd; | |
| 309 hash->dirty_mmap = TRUE; | |
| 310 return TRUE; | |
| 311 } | |
| 312 | |
| 313 off_t mail_hash_lookup_uid(MailHash *hash, unsigned int uid) | |
| 314 { | |
| 315 MailHashRecord *rec; | |
| 316 unsigned int hashidx, idx; | |
| 317 | |
| 318 i_assert(uid > 0); | |
| 319 i_assert(hash->index->lock_type != MAIL_LOCK_UNLOCK); | |
| 320 | |
| 321 if (hash->fd == -1 || !mmap_update(hash)) | |
| 322 return 0; | |
| 323 | |
| 324 /* our hashing function is simple - UID*2. The *2 is there because | |
| 325 UIDs are normally contiguous, so once the UIDs wrap around, we | |
| 326 don't want to go through lots of records just to find an empty | |
| 327 spot */ | |
| 328 hashidx = HASH_FUNC(uid) % hash->size; | |
| 329 rec = (MailHashRecord *) ((char *) hash->mmap_base + | |
| 330 sizeof(MailHashHeader)); | |
| 331 | |
| 332 /* check from hash index to end of file */ | |
| 333 for (idx = hashidx; idx < hash->size; idx++) { | |
| 334 if (rec[idx].uid == uid) | |
| 335 return rec[idx].position; | |
| 336 | |
| 337 if (rec[idx].uid == 0) { | |
| 338 /* empty hash record - not found. */ | |
| 339 return 0; | |
| 340 } | |
| 341 } | |
| 342 | |
| 343 /* check from beginning of file to hash index */ | |
| 344 for (idx = 0; idx < hashidx; idx++) { | |
| 345 if (rec[idx].uid == uid) | |
| 346 return rec[idx].position; | |
| 347 | |
| 348 if (rec[idx].uid == 0) { | |
| 349 /* empty hash record - not found. */ | |
| 350 return 0; | |
| 351 } | |
| 352 } | |
| 353 | |
| 354 /* checked through the whole hash file. this really shouldn't happen, | |
| 355 we should have rebuilt it long time ago.. */ | |
| 356 return 0; | |
| 357 } | |
| 358 | |
| 359 static MailHashRecord *hash_find_uid_or_free(MailHash *hash, unsigned int uid) | |
| 360 { | |
| 361 MailHashRecord *rec; | |
| 362 unsigned int hashidx, idx; | |
| 363 | |
| 364 hashidx = HASH_FUNC(uid) % hash->size; | |
| 365 rec = (MailHashRecord *) ((char *) hash->mmap_base + | |
| 366 sizeof(MailHashHeader)); | |
| 367 | |
| 368 /* check from hash index to end of file */ | |
| 369 for (idx = hashidx; idx < hash->size; idx++) { | |
| 370 if (rec[idx].uid == 0 || rec[idx].uid == uid) | |
| 371 return rec+idx; | |
| 372 } | |
| 373 | |
| 374 /* check from beginning of file to hash index */ | |
| 375 for (idx = 0; idx < hashidx; idx++) { | |
| 376 if (rec[idx].uid == 0 || rec[idx].uid == uid) | |
| 377 return rec+idx; | |
| 378 } | |
| 379 | |
| 380 /* hash file is full */ | |
| 381 return NULL; | |
| 382 } | |
| 383 | |
| 384 void mail_hash_update(MailHash *hash, unsigned int uid, off_t pos) | |
| 385 { | |
| 386 MailHashRecord *rec; | |
| 387 unsigned int max_used; | |
| 388 | |
| 389 i_assert(uid > 0); | |
| 390 i_assert(hash->index->lock_type == MAIL_LOCK_EXCLUSIVE); | |
| 391 | |
| 392 if (hash->fd == -1 || !mmap_update(hash)) | |
| 393 return; | |
| 394 | |
| 395 if (hash->header->used_records > | |
| 396 hash->size * FORCED_REBUILD_PERCENTAGE / 100) { | |
| 397 /* we really need a rebuild. */ | |
| 398 mail_hash_rebuild(hash); | |
| 399 } | |
| 400 | |
| 401 /* place the hash into first free record after wanted position */ | |
| 402 rec = hash_find_uid_or_free(hash, uid); | |
| 403 | |
| 404 if (rec == NULL) { | |
| 405 /* this should never happen, we had already checked that | |
| 406 at least 1/5 of hash was empty. except, if the header | |
| 407 contained invalid record count for some reason. rebuild.. */ | |
| 408 mail_hash_rebuild(hash); | |
| 409 | |
| 410 rec = hash_find_uid_or_free(hash, uid); | |
| 411 i_assert(rec != NULL); | |
| 412 } | |
| 413 | |
| 414 if (pos != 0) { | |
| 415 /* insert/update record */ | |
| 416 if (rec->uid == 0) { | |
| 417 /* update records count, and see if hash is | |
| 418 getting full */ | |
| 419 max_used = hash->size / 100 * REBUILD_PERCENTAGE; | |
| 420 if (++hash->header->used_records > max_used) { | |
| 421 hash->index->set_flags |= | |
| 422 MAIL_INDEX_FLAG_REBUILD_HASH; | |
| 423 } | |
| 424 } | |
| 425 rec->uid = uid; | |
| 426 rec->position = pos; | |
| 427 } else { | |
| 428 /* delete record */ | |
| 429 rec->uid = 0; | |
| 430 rec->position = 0; | |
| 431 hash->header->used_records--; | |
| 432 } | |
| 433 | |
| 434 hash->modified = FALSE; | |
| 435 } |